Active-active access to transparent interconnection of lots of links (TRILL) edges

ABSTRACT

A routing bridge at an edge of a transparent interconnection of lots of links (TRILL) campus, comprises a first access port and a second access port each designated as one of a multi-chassis link aggregation (MC-LAG) designated forward (DF) port and an MC-LAG non-DF port, wherein the first access port is associated with a first pseudo-nickname, and a second access port is associated with a second pseudo-nickname, wherein a frame received via the first access port from a first customer equipment (CE) is replicated to generate a replicated frame, wherein the replicated frame is forwarded via the second access port to a second CE when the first pseudo-nickname and the second pseudo-nickname are the same, and when the first pseudo-nickname and the second pseudo-nickname are different and the second access port has been designated as the MC-LAG DF port.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationNo. 61/992,767 filed May 13, 2014 by Donald Eastlake, et al., and titled“Processes for Implementing Active-Active Access to Trill Edges,” whichis incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

In traditional internet protocol (IP) version 4 (IPv4) and IP version 6(IPv6) networks, a node in multiple subnets may have multiple IPaddresses. Administration of the IPv4 and IPv6 networks is complicatedbecause routers have to reconfigure the IP address every time the nodemoves from one subnet to another one. Therefore, careful IP addressmanagement is required to avoid creating subnets that are sparselypopulated in order to save the IP addresses.

Transparent interconnection of lots of links (TRILL) protocols areproposed to address this issue as described in Internet Engineering TaskForce (IETF) Request for Comments (RFC) 6325, “Routing Bridges(RBridges): Base Protocol Specification,” which is incorporated hereinby reference (“IETF RFC 6325”).

SUMMARY

In one embodiment, the disclosure includes a routing bridge at an edgeof a transparent interconnection of lots of links (TRILL) campus,comprises a first access port designated as one of a multi-chassis linkaggregation (MC-LAG) designated forward (DF) port and an MC-LAG non-DFport, wherein the first access port is associated with a firstpseudo-nickname, and a second access port designated as one of theMC-LAG DF ports and MC-LAG non-DF ports, wherein the second access portis associated with a second pseudo-nickname, wherein a frame receivedvia the first access port from a first customer equipment (CE) isreplicated to generate a replicated frame, wherein the replicated frameis forwarded via the second access port to a second CE when the firstpseudo-nickname and the second pseudo-nickname are the same, and whenthe first pseudo-nickname and the second pseudo-nickname are differentand the second access port has been designated as the MC-LAG DF port,wherein the first pseudo-nickname and the second pseudo-nickname are thesame when the first CE coupled to the first access port and the secondCE coupled to the second access port are coupled to a same group ofrouting bridges, and wherein the first pseudo-nickname and the secondpseudo-nickname are different when the first CE and the second CE arecoupled to a different group of routing bridges.

In another embodiment, the disclosure includes a method for implementingactive-active access to edges of a TRILL campus, comprising designatinga first access port as one of an MC-LAG DF port and an MC-LAG non-DFport, wherein the first access port is associated with a firstpseudo-nickname, designating a second access port as one of the MC-LAGDF ports and MC-LAG non-DF ports, wherein a first CE coupled to thefirst access port and a second CE coupled to the second access port arecoupled to a same group of routing bridges, wherein the second accessport is associated with a second pseudo-nickname, wherein the secondpseudo-nickname and the first pseudo-nickname are the same, receiving aframe via the first access port from the first CE, replicating the frameto generate a replicated frame, and forwarding the replicated frame viathe second access port to the second CE.

In yet another embodiment, the disclosure includes a method forimplementing active-active access to edges of a TRILL campus, comprisingdesignating a first access port as one of an MC-LAG DF port and anMC-LAG non-DF port, wherein the first access port is associated with afirst pseudo-nickname, designating a second access port as one of theMC-LAG DF ports and MC-LAG non-DF ports, wherein a first CE coupled tothe first access port and a second CE coupled to the second access portare coupled to a different group of routing bridges, wherein the secondaccess port is associated with a second pseudo-nickname, wherein thesecond pseudo-nickname and the first pseudo-nickname are different,receiving a frame via the first access port from the first CE,replicating the frame to generate a replicated frame, and forwarding thereplicated frame via the second access port to the second CE when thesecond access port was designated as a MC-LAG DF port.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a schematic diagram of a network.

FIG. 2 is a schematic diagram of another network.

FIG. 3 is a schematic diagram of yet another network.

FIG. 4 is a schematic diagram of yet another network.

FIG. 5 is a schematic diagram of yet another network.

FIG. 6 is another schematic diagram of the network in FIG. 5.

FIG. 7 is yet another schematic diagram of the network in FIG. 5.

FIG. 8 is a flowchart illustrating a method for implementingactive-active access to edges of a transparent interconnection of lotsof links (TRILL) campus according to an embodiment of the disclosure.

FIG. 9 is a flowchart illustrating a method for replicating a frame forforwarding according to an embodiment of the disclosure.

FIG. 10 is a flowchart illustrating another method for implementingactive-active access to edges of a TRILL campus.

FIG. 11 is a flowchart illustrating a method for implementingactive-active access to edges of a TRILL campus according to anotherembodiment of the disclosure.

FIG. 12 is a flowchart illustrating a method for implementingactive-active access to edges of a TRILL campus according to yet anotherembodiment of the disclosure.

DETAILED DESCRIPTION

It should be understood at the outset that, although illustrativeimplementations of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

FIG. 1 is a schematic diagram of a network 100. The network 100comprises a transparent interconnection of lots of links (TRILL) campus110 and two pieces of customer equipment (CE) 150 (e.g. CE1 and CE2).The network 100 may be configured as shown or in any other suitablemanner.

The TRILL campus 110 comprises a plurality of routing bridges (RBs) 120,which are interconnected. FIG. 1 shows three RBs 120 (e.g. RB1, RB2, andrb3) at an edge of the TRILL campus 110. The RBs 120 are configured toforward frames in the TRILL campus 110. In an embodiment, the RBs 120are routers. In another embodiment, the RBs 120 are any other networkcomponents that are configured to forward frames, for example, switches.The CE 150 may be a computer or a server and configured to transmit theframes to the TRILL campus 110 or receive the frames from the TRILLcampus 110. The RBs 120 at the edge of the TRILL campus 110 (e.g. RB1,RB2, and rb3) and CEs 150 are coupled with links 130, which may beeither wireless channels or cables.

The Internet Engineering Task Force (IETF) Request for Comments (RFC)6325 describes a system that has excellent performance in load sharingand failure recovery inside the TRILL campus 110. However, at the edges,the IETF RFC 6325 provides limited load sharing across links 130 and mayrespond slowly to failures in the RBs 120 and links 130.

An active-active access in the network utilizes multi-chassis linkaggregation (MC-LAG) 140 (e.g. MC-LAG1, and MC-LAG2) to connect a groupof RBs 120 at the edge of the TRILL campus 110 to CEs 150 via accessports 135, which enables efficient traffic load spread from RBs 120 toCEs 150. Additionally, the active-active access provides highreliability by allowing for rapid failure detection. The IETF RFC 6325requires that only one of a group of RBs 120 is able to forward a frameas an appointed forwarder to one or more CEs 150 which are connectedwith the group of RBs 120. However, the IETF RFC 6325 may not guaranteeactive-active access under some circumstances. For example, as shown inFIG. 1, multiple links 130 are connected to CE1 150. Every RB 120forwards a “Hello” frame to CE1 150. One RB 120 may not see the “Hello”message from another RB 120. Therefore, every RB 120 thinks of itself asthe appointed forwarder.

There are numerous problems to overcome with implementing active-activeaccess in a network. FIGS. 2-4 show three major problems with possiblesolutions. These problems and solutions are enumerated in IETF RFC 7379,“Problem Statement and Goals for Active-active access at the TransparentInterconnection of Lots of Links (TRILL) Edge,” which is incorporatedherein by reference.

FIG. 2 is a schematic diagram of another network 200. The network 200comprises a TRILL campus 210 and a CE 270. The TRILL campus 210 and theCE 270 are similar to the TRILL campus 110 and the CE 150. FIG. 2 showsRB1 230, RB2 240, and RB3 250 at an edge of the TRILL campus 210 and RBn220 at another edge of the TRILL campus 210. RB1 230, RB2 240, RB3 250,and RBn 220 are similar to the RBs 120 in FIG. 1. Also similar to FIG.1, an active-active access in the network 200 utilizes MC-LAG 260 toconnect RB1 230, RB2 240, and RB3 250 to the CE 270 via an access port235 of RB1 230, an access port 245 of RB2 240, and an access port 255 ofRB3 250, respectively.

After RBn 220 sends a multi-destination TRILL data frame into the TRILLcampus 210, each of RB1 230, RB2 240, and RB3 250 receives the TRILLdata frame, and forward the payload frame inside that TRILL data frameto the CE 270 utilizing the MC-LAG 260. The payload frame may be one ofa broadcast frame, a unicast frame, and a multicast frame. Therefore,the payload frame is generally referred to as a flooded broadcast,unicast, or multicast (BUM) data frame. One problem with such aconfiguration is that the CE 270 receives the same frame from each ofRB1 230, RB2 240, and RB3 250, which is unnecessary and may confuse 270.A possible solution is to assign one of the access port 235 of RB1 230,the access port 245 of RB2 240, and the access port 255 of RB3 250 as adesignated forwarder (DF) port. Only the DF port is allowed to forwardthe payload frame to the CE 270.

FIG. 3 is a schematic diagram of yet another network 300. The network300 comprises a TRILL campus 310 and a CE 360. The TRILL campus 310 andthe CE 360 are similar to the TRILL campus 110 and the CE 150. FIG. 3shows RB1 320, RB2 330, and RB3 340 at an edge of the TRILL campus 310,which are similar to RB1 120 in FIG. 1. Similar to FIG. 1, anactive-active access in the network 300 utilizes MC-LAG 350 to connectRB1 320, RB2 330, and RB3 340 to the CE 360 via an access port 325 ofRB1 320, an access port 335 of RB2 330, and an access port 345 of RB3340, respectively.

After receipt of a BUM data frame from the CE 360, RB1 320 encapsulatesthe BUM data frame as the payload of a multi-destination TRILL dataframe and sends the multi-destination TRILL data frame into the TRILLcampus 310. Both RB2 330 and RB3 340 receive the frame. A problem isboth RB2 330 and RB3 340 may forward the frame to the CE 360, whichtransmitted the frame originally. Therefore, a loop is formed. Apossible solution is to assign pseudo-nicknames to the access port 325of RB1 320, the access port 335 of RB2 330, and the access port 345 ofRB3 340. Since all the access port 325 of RB1 320, the access port 335of RB2 330, and the access port 345 of RB3 340 are associated with thesame MC-LAG 350, they are considered as virtual RBs and are assigned thesame pseudo-nickname. RB1 320 encapsulates the frame with thispseudo-nickname and sends the encapsulated frame into the TRILL campus.Upon receipt of the encapsulated frame, RB2 330 and RB3 340 decapsulatethe encapsulated frame, and obtain the pseudo-nicknames and the frames.RB2 330 and RB3 340 do not forward the frames to the CE 360 since thepseudo-nicknames obtained from the encapsulated frames are the same asthe pseudo-nicknames associated with the access port 335 of RB2 330 andthe access port 345 of RB3 340. Therefore, the loop is avoided. However,a huge number of pseudo-nicknames may be needed in a complex networkwith a large number of MC-LAGs, which may result in memory overflow.

FIG. 4 is a schematic diagram of yet another network 400. The network400 comprises a TRILL campus 420, CE1 480, and CE2 410. The TRILL campus420 is similar to the TRILL campus 110. CE1 480 and CE2 410 are similarto the CE 150. FIG. 4 shows RB1 440, RB2 450, and RB3 460 at an edge ofthe TRILL campus 420 and RBn 430 at another edge of the TRILL campus420. RB1 440, RB2 450, RB3 460, and RBn 430 are similar to RB1 120 inFIG. 1. Similar to FIG. 1, an active-active access in the network 400utilizes MC-LAG 470 to connect RB1 440, RB2 450, and RB3 460 to CE1 480via an access port 445 of RB1 440, an access port 455 of RB2 450, and anaccess port 465 of rb3, respectively.

As shown in FIG. 4, CE1 480 sends frames to RB1 440, RB2 450, and RB3460 with the same source media access control (MAC) address, the choicebetween RB1 440, RB2 450, or RB3 460 being made by MC-LAG 470. Each ofthe RBs which receive a frame (e.g., RB1 440, RB2 450, or RB3 460) mayencapsulate the frame with its own individual nickname, and send theencapsulated frame to the TRILL campus 420. RBn 430 receives all theencapsulated frames, which comprise the same source MAC address but withdifferent nicknames. This may be regarded as a severe network problem byRBn 430 and RBn 430 might discard such traffic and notify the networkoperator or engage in other undesired behavior. As a consequence, RBn430 may encapsulate returned frames from CE2 410 destined for CE1 480into the TRILL campus 420 using the nickname for RB1 440, RB2 450, orRB3 460, causing the encapsulated frames to go through different pathsback to CE1 480, which may result in persistent reordering of theframes. Assigning the same pseudo-nickname to the access port 445 of RB1440, the access port 455 of RB2 450, and the access port 465 of RB3 460may solve the problems. However, as discussed above, a huge number ofpseudo-nicknames may be needed in a complex network with a large numberof MC-LAGs 470, which may result in memory overflow.

Disclosed herein are embodiments for implementing active-active accesson TRILL edges. The disclosed embodiments may reduce usage of nicknamesby about two orders of magnitude by assigning pseudo-nicknames on accessports of RBs. The RBs at an edge of a TRILL campus designate each accessport as one of an MC-LAG DF port, an MC-LAG non-DF port, and a nonMC-LAG port. Each access port is associated with a pseudo-nickname aslong as the access port is not a non MC-LAG port. For example, a firstaccess port is associated with a first pseudo-nickname, and a secondaccess port is associated with a second pseudo-nickname. The firstpseudo-nickname and the second pseudo-nickname are the same when a firstCE coupled to the first access port and a second CE coupled to thesecond access port are coupled to the same group of the RBs. In thiscase, a frame received via the first access port from the first CE isreplicated, and the replicated frame is then forwarded via the secondaccess port to the second CE. On the other hand, the firstpseudo-nickname and the second pseudo-nickname are different when thefirst CE and the second CE are coupled to a different group of the RBs.In this case, the frame received via the first access port from thefirst CE is replicated and the replicated frame is then forwarded viathe second access port to the second CE only when the second access portis designated as a MC-LAG DF port. Each RB may have more than two accessports, which may be coupled to more than two CEs.

FIG. 5 is a schematic diagram of yet another network 500. The network500 comprises a TRILL campus 510, CE1 555, CE2 565, and CE3 575. Thenetwork 500 may be configured as shown or in any other suitable manner.

The TRILL campus 510 comprises a plurality of RBs, including RB1 520,RB2 530, and RB3 540 at the edge of the TRILL campus 510. The TRILLcampus 510 and the RBs (e.g. RB1 520, RB2 530, and RB3 540) are similarto the TRILL campus 110 and RBs 120 in FIG. 1. In an embodiment, theRBs, including RB1 520, RB2 530, and RB3 540 are routers. In anotherembodiment, the RBs, including RB1 520, RB2 530, and RB3 540 are anyother network components that are configured to forward frames, forexample switches. RB1 520 comprises a first access port 522 and a secondaccess port 524. RB2 530 comprises a first access port 532, a secondaccess port 534, and a third access port 536. RB3 540 comprises a firstaccess port 542, a second access port 544, and a third access port 546.

The CEs (e.g. CE1 555, CE2 565, and CE3 575) are similar to the CEs 150in FIG. 1. In an embodiment, each of CE1 555, CE2 565, and CE3 575 isone of a computer and a server. An active-active access in the network500 utilizes MC-LAG1 550 to connect RB1 520, RB2 530, and RB3 540 to CE1555 via the first access port 522 of RB1 520, the first access port 532of RB2 530, and the first access port 542 of RB3 540, respectively. Theactive-active access in the network 500 utilizes MC-LAG2 560 to connectRB1 520, RB2 530, and RB3 540 to CE2 565 via the second access port 524of RB1 520, the second access port 534 of RB2 530, and the second accessport 544 of RB3 540, respectively. The active-active access in thenetwork 500 utilizes MC-LAG3 570 to connect RB2 530 and RB3 540 to CE3575 via the third access port 536 of RB2 530 and the third access port546 of RB3 540, respectively.

Before implementing active-active access on TRILL edges, each accessport of the RBs is designated as one of a non MC-LAG port, an MC-LAGnon-DF port, and an MC-LAG DF port. When an access port is notassociated with an MC-LAG, the access port of the RB is a non MC-LAGport. Otherwise, the access port is either an MC-LAG non-DF port or anMC-LAG DF port and is generally referred to as an MC-LAG port. Only oneaccess port associated with an MC-LAG is designated as an MC-LAG DFport. The MC-LAG DF port may be selected arbitrarily for each MC-LAG.All other access ports associated with the MC-LAG excluding the MC-LAGDF port are designated as MC-LAG non-DF ports. For example, all theaccess ports in FIG. 5 are associated with MC-LAG1 550, MC-LAG2 560, orMC-LAG3 570. Therefore, the access ports in FIG. 5 are either MC-LAG DFports or MC-LAG non-DF ports. There are numerous ways of assigningMC-LAG DF ports and MC-LAG non-DF ports. FIG. 6 and FIG. 7 show twoexamples.

FIG. 6 is another schematic diagram of the network 500 in FIG. 5. As canbe seen, the first access port 522 of RB1 520, the second access port534 of RB2 530, and the third access port 546 of RB3 540 are designatedas MC-LAG DF ports. On the other hand, the second access port 524 of RB1520, the first access port 532 of RB2 530, the third access port 536 ofRB2 530, the first access port 542 of RB3 540, and the second accessport 544 are designated as MC-LAG non-DF ports.

FIG. 7 is yet another schematic diagram of the network 500 in FIG. 5. Ascan be seen, the first access port 522 of RB1 520, the second accessport 524 of RB1 520, and the third access port 546 of RB3 540 aredesignated as MC-LAG DF ports. On the other hand, the first access port532 of RB2 530, the second access port 534 of RB2 530, the third accessport 536 of RB2 530, the first access port 542 of RB3 540, and thesecond access port 544 of RB3 540 are designated as MC-LAG non-DF ports.When an access port is an MC-LAG port, the access port is associatedwith a pseudo-nickname. For example, a first access port is associatedwith a first pseudo-nickname, and a second access port is associatedwith a second pseudo-nickname. The first pseudo-nickname and the secondpseudo-nickname are the same when a first CE coupled to the first accessport and a second CE coupled to the second access port are coupled tothe same group of RBs. For example, as shown in FIGS. 5-7, the firstaccess port 522 of RB1 520 is coupled to CE1 555. The second access port524 of RB1 520 is coupled to CE2 565. Both CE1 555 and CE2 565 arecoupled to a same first group of RBs, including RB1 520, RB2 530, andRB3 540. Therefore, the first access port 522 of RB1 520 and the secondaccess port 524 of RB1 520 are associated with a same pseudo-nickname,PN1. Similarly, the first access port 532 of RB2 530, the second accessport 534 of RB2 530, the first access port 542 of RB3 540 and the secondaccess port 544 of RB3 540 are all associated with the samepseudo-nickname, PN1.

On the other hand, the third access port 536 of RB2 530 and the thirdaccess port 546 of RB3 540 are both coupled to CE3 575, which is coupledto a same second group of RBs, including only RB2 530 and RB3 540.Therefore, the third access port 536 of RB2 530 and the third accessport 546 of RB3 540 are associated with a same pseudo-nickname, PN2,different from PN1.

FIG. 8 is a flowchart illustrating a method 800 for implementingactive-active access to edges of a TRILL campus according to anembodiment of the disclosure. The method 800 may be implemented in aningress RB to ensure that a frame received by the ingress RB from afirst CE is forwarded to other CEs. The frame may be one of a broadcastframe, a unicast frame, and a multicast frame. Therefore, the frame isgenerally referred to as a BUM data frame. The ingress RB is located atan edge of the TRILL campus and is configured to receive the framedirectly from the first CE. For example, the ingress RB is RB1 520 inFIG. 6 and RB2 530 in FIG. 7. The first CE is CE1 555 in FIG. 6 and FIG.7.

At block 810, the frame is received from the first CE via a first accessport. For instance, in FIG. 6, a frame is received from CE1 555 via thefirst access port 522 of RB1 520. For another instance, in FIG. 7, aframe is received from CE1 555 via the first access port 532 of RB2 530.

At block 820, it is determined whether the first access port is a nonMC-LAG port. If the first access port is a non MC-LAG port, the method800 proceeds to block 860. At block 860, the IETF RFC 6325 should befollowed. The method for implementing the active-active access to edgesof a TRILL campus via non MC-LAG ports is well described in IETF RFC6325. If the first access port is not a non MC-LAG port, the method 800proceeds to block 830. For instance, in FIG. 6, the first access port522 of RB1 520 is not a non MC-LAG port. Therefore, the method 800proceeds to block 830. For another instance, in FIG. 7, the first accessport 532 of RB2 530 is not a non MC-LAG port. Therefore, the method 800proceeds to block 830.

At block 830, the frame is replicated for forwarding. Block 830 isdescribed in further detail in FIG. 9. At block 840, the frame isencapsulated with a first pseudo-nickname associated with the firstaccess port. For instance, in both FIG. 6 and FIG. 7, the frame isencapsulated with the first pseudo-nickname PN1. Finally, at block 850,the encapsulated frame is sent into the TRILL campus. For instance, inboth FIG. 6 and FIG. 7, the encapsulated frame is sent into the TRILLcampus 510.

FIG. 9 is a flowchart illustrating a method 900 for replicating a framefor forwarding, for example, replicating the frame for forwarding asdescribed in block 830 in FIG. 8 according to an embodiment of thedisclosure. The method 900 is implemented in an ingress RB to ensurethat the frame received by the ingress RB from a first CE is forwardedto other CEs. For example, the ingress RB is RB1 520 in FIG. 6 and RB2530 in FIG. 7. The first CE is CE1 555 in FIG. 6 and FIG. 7.

At block 831, it is determined whether there is any other access port.If there is no other access port, the method 900 is finished. If thereis other access port, the method 900 proceeds to block 832. Forinstance, in FIG. 6, RB1 520 determines whether there is any access portother than the first access port 522 of RB1 520. The second access port524 of RB1 520 is such an access port. Therefore, the method 900proceeds to block 832. For another instance, in FIG. 7, RB2 530determines whether there is any access port other than the first accessport 532 of RB2 530. The second access port 534 of RB2 530 is such anaccess port. Therefore, the method 900 proceeds to block 832.

At block 832, it is determined whether the other access port is a nonMC-LAG port. If the new access port is a non MC-LAG port, the method 900is finished. If the new access port is not a non MC-LAG port, the method900 proceeds to block 833. For instance, in FIG. 6, RB1 520 determinesthe second access port 524 of RB1 520 is not a non MC-LAG port.Therefore, the method 900 proceeds to block 833. For another instance,in FIG. 7, RB2 530 determines the second access port 534 of RB2 530 isnot a non MC-LAG port. Therefore, the method 900 proceeds to block 833.

At block 833, it is determined whether the pseudo-nickname of the otheraccess port is the same as the first pseudo-nickname. If thepseudo-nickname of the other access port is the same as the firstpseudo-nickname, the method 900 proceeds to block 837. If thepseudo-nickname of the other access port is different from the firstpseudo-nickname, the method 900 proceeds to block 835. For instance, inFIG. 6, RB1 520 determines the pseudo-nickname of the second access port524 of RB1 520 is the same as the first pseudo-nickname, PN1. Therefore,the method 900 proceeds to block 837. For another instance, in FIG. 7,RB2 530 determines the pseudo-nickname of the second access port 534 ofRB2 530 is the same as the first pseudo-nickname, PN1. Therefore, themethod 900 proceeds to block 837.

At block 835, it is determined whether the other access port is anMC-LAG DF port. If the other access port is an MC-LAG DF port, themethod 900 proceeds to block 837. If the other access port is an MC-LAGnon-DF port, the method 900 proceeds back to block 831.

At block 837, the received frame is replicated. In an embodiment, thereceived frame may be replicated before the decision of block 833 ismade. In such an embodiment, the method would proceed directly fromblock 833 or block 835 to block 839. At block 839, the replicated frameis forwarded via the other access port to a CE that the other accessport is coupled with. The method 900 then proceeds back to block 831.For instance, in FIG. 6, the replicated frame is forwarded via thesecond access port 524 of RB1 520 to CE2 565. The method 900 thenproceeds back to block 831. For another instance, in FIG. 7, thereplicated frame is forwarded via the second access port 534 to CE2 565.The method 900 then proceeds back to block 831.

FIG. 10 is a flowchart illustrating another method 1000 for implementingactive-active access to edges of a TRILL campus. The method 1000 may beimplemented in an egress RB to ensure that the frame received by theingress RB from the first CE is forward to other CEs that are coupled tothe egress RB. The egress RB is located at the edge of the TRILL campusand is configured to forward the frame directly to the other CEs thatare coupled to the egress RB. For example, the egress RB is RB2 530 inFIG. 6 and RB3 540 in FIG. 7.

At block 1010, the encapsulated frame is received from the TRILL campus.At block 1015, the received encapsulated frame is decapsulated to obtainthe frame and the first pseudo-nickname. For instance, in FIG. 6, RB2530 receives the encapsulated frame, and then decapsulates it to obtainthe first pseudo-nickname PN1 and the frame. For another instance, inFIG. 7, RB3 540 receives the encapsulated frame and decapsulates it toobtain the first pseudo-nickname PN1 and the frame.

At block 1017, an access port is found. For instance, in FIG. 6, thefirst access port 532 of RB2 530 is found. For another instance, in FIG.7, the third access port 546 of RB3 540 is found.

At block 1020, it is determined whether the access port is a non MC-LAGport. If the access port is a non MC-LAG port, the method 1000 proceedsto block 1040. At block 1040, the IETF RFC 6325 is followed. Then themethod 1000 proceeds to block 1080. If the access port is not a nonMC-LAG port, the method 1000 proceeds to block 1030. For instance, inFIG. 6, RB2 530 determines the first access port 532 of RB2 530 is not anon MC-LAG port. Therefore, the method 1000 proceeds to block 1030. Foranother instance, in FIG. 7, RB3 540 determines the third access port546 of RB3 540 is not a non MC-LAG port. Therefore, the method 1000proceeds to block 1030.

At block 1030, it is determined whether the pseudo-nickname of theaccess port is the same as the first pseudo-nickname. If thepseudo-nickname of the access port is the same as the firstpseudo-nickname, the method 1000 proceeds to block 1080. If thepseudo-nickname of the access port is different from the firstpseudo-nickname, the method 1000 proceeds to block 1050. For instance,in FIG. 6, RB2 530 determines the pseudo-nickname of the first accessport 532 of RB2 530 is the same as the first pseudo-nickname, PN1.Therefore, the method 1000 proceeds to block 1080. For another instance,in FIG. 7, RB3 540 determines the pseudo-nickname of the third accessport 546 of RB3 540, PN2 is different from the first pseudo-nickname,PN1. Therefore, the method 1000 proceeds to block 1050.

At block 1050, it is determined whether the access port is an MC-LAG DFport. If the access port is an MC-LAG DF port, the method 1000 proceedsto block 1060. If the access port is not an MC-LAG DF port indicating anMC-LAG non-DF port, the method 1000 proceeds to block 1080. Forinstance, in FIG. 7, RB3 540 determines the third access port 546 of RB3540 is an MC-LAG DF port. Therefore, the method 1000 proceeds to block1060.

At block 1060, the frame is replicated. For instance, in FIG. 7, RB3 540replicates the frame to generate a replicated frame. At block 1070, thereplicated frame is forwarded via the access port. For instance, in FIG.7, the replicated frame is forwarded via the third access port 546 ofRB3 540 to CE3 575.

At block 1080, it is determined whether there is any other access portfound in the egress RB. If there is other access port found in theegress RB, the method 1000 returns to the block 1020. If there is noother access port in the egress RB, the method 1000 proceeds to block1090. For instance, in FIG. 6, RB2 530 determines there are other accessports other than the first access port 532 in RB2 530, including thesecond access port 534 of RB2 530 and the third access port 536 of RB2530. Therefore, in FIG. 6, the method 1000 may proceed with either thesecond access port 534 of RB2 530 or the third access port 536 of RB2530 to block 1020. For another instance, in FIG. 7, RB3 540 determinesthere are other access ports other than the third access port 546 in RB3540, including the first access port 542 of RB3 540 and the secondaccess port 544 of RB3 540. Therefore, in FIG. 7, the method 1000 mayproceed with either the first access port 542 of RB3 540 or the secondaccess port 544 of RB3 540 to block 1020.

Finally, when the egress RB determines there is no other access portfound at block 1080, the method 1000 proceeds to block 1090. At block1090, the frame is discarded. The method 1000 is then finished.

FIG. 11 is a flowchart illustrating a method 1100 for implementingactive-active access to edges of a TRILL campus according to anotherembodiment of the disclosure. The method 1100 is implemented in aningress RB to ensure that a frame received by the ingress RB from afirst CE is forwarded to other CEs. The frame may be one of a broadcastframe, a unicast frame, and a multicast frame. Therefore, the frame isgenerally referred to as a BUM data frame. The ingress RB may be RB1 520in FIG. 6 and RB2 530 in FIG. 7. In an embodiment, the ingress RB is arouter.

At block 1110, a first access port is designated as one of an MC-LAG DFport and an MC-LAG non-DF port, wherein the first access port isassociated with a first pseudo-nickname. At block 1120, a second accessport is designated as one of the MC-LAG DF ports and MC-LAG non-DFports, wherein the first CE coupled to the first access port and asecond CE coupled to the second access port are coupled to a same groupof RBs, wherein the second access port is associated with a secondpseudo-nickname, wherein the second pseudo-nickname and the firstpseudo-nickname are the same. In an embodiment, each of the first CE andthe second CE is one of a computer and a server.

At step 1130, a frame is received via the first access port from thefirst CE. In an embodiment, the frame is a BUM data frame. At step 1140,the frame is replicated to generate a replicated frame. At step 1150,the replicated frame is forwarded via the second access port to thesecond CE.

FIG. 12 is a flowchart illustrating a method 1200 for implementingactive-active access to edges of a TRILL campus according to yet anotherembodiment of the disclosure. The method 1200 may be implemented in aningress RB to ensure that a frame received by the ingress RB from afirst CE is forwarded to other CEs. For example, the ingress RB is RB1520 in FIG. 6 and RB2 530 in FIG. 7. In an embodiment, the ingress RB isa router. The frame may be one of a broadcast frame, a unicast frame,and a multicast frame. Therefore, the frame is generally referred to asa BUM data frame.

At block 1210, a first access port is designated as one of an MC-LAG DFport and an MC-LAG non-DF port, wherein the first access port isassociated with a first pseudo-nickname. At block 1220, a second accessport is designated as one of the MC-LAG DF ports and MC-LAG non-DFports, wherein the first CE coupled to the first access port and asecond CE coupled to the second access port are coupled to a differentgroup of RBs, wherein the second access port is associated with a secondpseudo-nickname, and wherein the second pseudo-nickname and the firstpseudo-nickname are different. In an embodiment, each of the first CEand the second CE is one of a computer and a server.

At block 1230, a frame is received via the first access port from thefirst CE. In an embodiment, the frame is a BUM data frame. At block1240, the frame is replicated to generate a replicated frame. At block1250, the replicated frame is forwarded via the second access port tothe second CE when the second access port was designated as a MC-LAG DFport.

While several embodiments have been provided in the present disclosure,it may be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and may be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. A routing bridge at an edge of a transparentinterconnection of lots of links (TRILL) campus, comprising: a firstaccess port designated as one of a multi-chassis link aggregation(MC-LAG) designated forwarder (DF) port and an MC-LAG non-DF port,wherein the first access port is associated with a firstpseudo-nickname; and a second access port designated as one of theMC-LAG DF ports and MC-LAG non-DF ports, wherein the second access portis associated with a second pseudo-nickname, wherein a frame receivedvia the first access port from a first customer equipment (CE) isreplicated to generate a replicated frame, wherein the replicated frameis forwarded via the second access port to a second CE when the firstpseudo-nickname of the routing bridge and the second pseudo-nickname ofthe routing bridge are the same, and when the first pseudo-nickname ofthe routing bridge and the second pseudo-nickname of the routing bridgeare different and the second access port has been designated as theMC-LAG DF port, wherein the first pseudo-nickname and the secondpseudo-nickname are the same when the first CE coupled to the firstaccess port and the second CE coupled to the second access port arecoupled to a same group of routing bridges, and wherein the firstpseudo-nickname and the second pseudo-nickname are different when thefirst CE and the second CE are coupled to a different group of routingbridges.
 2. The routing bridge of claim 1, wherein the routing bridge isconfigured to encapsulate the frame to generate an encapsulated frame.3. The routing bridge of claim 2, wherein the encapsulated frame isassociated with the first pseudo-nickname.
 4. The routing bridge ofclaim 3, wherein the routing bridge is configured to distribute theencapsulated frame into the TRILL campus.
 5. The routing bridge of claim1, wherein the routing bridge is a router.
 6. The routing bridge ofclaim 1, wherein the frame is a flooded broadcast, a flooded unicast, ora flooded multicast data frame.
 7. The routing bridge of claim 1,wherein each of the first CE and the second CE is one of a computer anda server.
 8. A method for implementing active-active access to edges ofa transparent interconnection of lots of links (TRILL) campus,comprising: designating a first access port of a routing bridge as oneof a multi-chassis link aggregation (MC-LAG) designated forwarder (DF)port and an MC-LAG non-DF port, wherein the first access port isassociated with a first pseudo-nickname; designating a second accessport of the routing bridge as one of the MC-LAG DF ports and MC-LAGnon-DF ports, wherein a first customer equipment (CE) coupled to thefirst access port and a second CE coupled to the second access port arecoupled to a same group of routing bridges, wherein the second accessport is associated with a second pseudo-nickname; receiving a frame viathe first access port from the first CE; replicating the frame togenerate a replicated frame; and forwarding the replicated frame via thesecond access port to the second CE when the second pseudo-nickname ofthe routing bridge and the first pseudo-nickname of the routing bridgeare the same.
 9. The method of claim 8, further comprising encapsulatingthe frame to generate an encapsulated frame.
 10. The method of claim 9,wherein the encapsulated frame is associated with the firstpseudo-nickname.
 11. The method of claim 10, further comprisingmulticasting the encapsulated frame to the TRILL campus.
 12. The methodof claim 8, wherein the routing bridge is a router.
 13. The method ofclaim 8, wherein the frame is a flooded broadcast, unicast, or multicast(BUM) data frame.
 14. The method of claim 8, wherein each of the firstCE and the second CE is one of a computer and a server.
 15. A method forimplementing active-active access to edges of a transparentinterconnection of lots of links (TRILL) campus, comprising: designatinga first access port of a routing bridge as one of a multi-chassis linkaggregation (MC-LAG) designated forwarder (DF) port and an MC-LAG non-DFport, wherein the first access port is associated with a firstpseudo-nickname; designating a second access port of the routing bridgeas one of the MC-LAG DF ports and MC-LAG non-DF ports, wherein a firstcustomer equipment (CE) coupled to the first access port and a second CEcoupled to the second access port are coupled to a different group ofrouting bridges, wherein the second access port is associated with asecond pseudo-nickname; receiving a frame via the first access port fromthe first CE; replicating the frame to generate a replicated frame; andforwarding the replicated frame via the second access port to the secondCE when the second pseudo-nickname of the routing bridge and the firstpseudo-nickname of the routing bridge are different, and the secondaccess port was designated as the MC-LAG DF port.
 16. The method ofclaim 15, further comprising encapsulating the frame to generate anencapsulated frame.
 17. The method of claim 16, wherein the encapsulatedframe is associated with the first pseudo-nickname.
 18. The method ofclaim 17, further comprising multicasting the encapsulated frame to theTRILL campus.
 19. The method of claim 15, wherein the routing bridge isa router.
 20. The method of claim 15, wherein the frame is a floodedbroadcast, unicast, or multicast (BUM) data frame.
 21. A method forimplementing active-active access to edges of a transparentinterconnection of lots of links (TRILL) campus, comprising: designatinga first access port of a routing bridge as a multi-chassis linkaggregation (MC-LAG) non-designated forwarder (non-DF) port, wherein thefirst access port is associated with a first pseudo-nickname;designating a second access port of the routing bridge as a MC-LAGdesignated forwarder (DF) port, wherein a first customer equipment (CE)coupled to the first access port and a second CE coupled to the secondaccess port are coupled to a same group of routing bridges, wherein thesecond access port is associated with a second pseudo-nickname;receiving a frame via the first access port from the first CE;replicating the frame to generate a replicated frame; when the secondpseudo-nickname of the routing bridge and the first pseudo-nickname ofthe routing bridge are the same, forwarding the replicated frame via thesecond access port to the second CE; and when the second pseudo-nicknameof the routing bridge and the first pseudo-nickname of the routingbridge are different and the second access port of the routing bridgewas designated as the MC-LAG DF port, forwarding the replicated framevia the second access port to the second CE.
 22. A method of providingactive-active access to a transparent interconnection of lots of links(TRILL) campus implemented by a routing bridge having a first accessport associated with a first customer equipment (CE) and a second accessport associated with a second CE, comprising: receiving, by the routingbridge, a frame from the first CE via the first access port;replicating, by the routing bridge, the frame to generate a replicatedframe; determining, by the routing bridge, that a pseudo-nicknameassociated with the first access port and the pseudo-nickname associatedwith the second access port are the same and that the first access portand the second access port are associated with different multi-chassislink aggregations (MC-LAGs); and forwarding, by the routing bridge, thereplicated frame to the second CE using the second access port.
 23. Themethod of claim 22, further comprising encapsulating the frame togenerate an encapsulated frame.
 24. The method of claim 23, wherein theencapsulated frame is associated with the pseudo-nickname.
 25. Themethod of claim 24, further comprising multicasting the encapsulatedframe to the TRILL campus.
 26. The method of claim 22, wherein therouting bridge is a router.
 27. The method of claim 22, wherein theframe is a flooded broadcast, unicast, or multicast (BUM) data frame.28. A method of providing active-active access to a transparentinterconnection of lots of links (TRILL) campus implemented by a routingbridge having a first access port associated with a first customerequipment (CE) and a second access port associated with a second CE,comprising: receiving, by the routing bridge, a frame from the first CEvia the first access port; replicating, by the routing bridge, the frameto generate a replicated frame; determining, by the routing bridge, thata pseudo-nickname associated with the first access port and apseudo-nickname associated with the second access port are different andthat the second access port is a designated forwarding port; andforwarding, by the routing bridge, the replicated frame to the second CEusing the second access port.
 29. The method of claim 28, furthercomprising encapsulating the frame to generate an encapsulated frame.30. The method of claim 29, wherein the encapsulated frame is associatedwith the pseudo-nickname associated with the first access port.
 31. Themethod of claim 30, further comprising multicasting the encapsulatedframe to the TRILL campus.
 32. The method of claim 28, wherein therouting bridge is a router.
 33. The method of claim 28, wherein theframe is a flooded broadcast, unicast, or multicast (BUM) data frame.